George RR Martin has promised that the ending of his bestselling A Song of Ice and Fire series will be “bittersweet”, rather than apocalyptic.

A sprawling slice of epic fantasy inspired by the Wars of the Roses, Martin’s series made its debut in 1996. Now adapted into the hit television show A Game of Thrones, it currently stretches to five doorstopper novels that have sold more than 58m copies worldwide, with a further two planned. Martin is currently writing the sixth title, The Winds of Winter; the author has described the wildly anticipated novel as “the son of Kong” – the monkey on his back.

When asked by the US paper the Observer’s television critic Sean T Collins whether “everyone will lose – whether it will end in some horrible apocalypse”, Martin admitted that he hadn’t written the ending yet, “but no”.

“That’s certainly not my intent,” said the novelist. “I’ve said before that the tone of the ending that I’m going for is bittersweet. I mean, it’s no secret that Tolkien has been a huge influence on me, and I love the way he ended Lord of the Rings. It ends with victory, but it’s a bittersweet victory.”

Tolkien’s epic ends with Frodo, Sam and the forces of good victorious over Sauron, but the now nine-fingered Hobbit “is never whole again, and he goes away to the Undying Lands, and the other people live their lives”, said Martin.

He also hailed “the scouring of the Shire”, in which the Hobbits return home to find the Shire in the hands of Saruman and Wormtongue. It’s a “brilliant piece of work, which I didn’t understand when I was 13 years old: ‘Why is this here? The story’s over?’” said Martin. “But every time I read it I understand the brilliance of that segment more and more. All I can say is that’s the kind of tone I will be aiming for. Whether I achieve it or not, that will be up to people like you and my readers to judge.”